DECALCIFICATION Flashcards

1
Q

When should decalcification be done?

A

Decalcification should be done AFTER FIXATION and BEFORE IMPREGNATION to ensure and facilitate normal cutting of bony tissue sections

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2
Q

Recommended ratio of fluid to tissue volume for decalcification:

A

20:1

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3
Q

Ideal time required for decalcifying tissue is

A

24 to 48 hours

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4
Q

Decalcifying of dense bones require up to _____ days

A

14 days

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5
Q

FACTORS INFLUENCING THE RATE OF DECALCIFICATION:

A
  1. Concentration of decalcifying agent
  2. Ratio of decalcifying fluid to tissue
  3. Temperature
  4. Mechanical agitation
  5. Ideal time required
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6
Q

ideal temperature for decalcification:

A

18 - 30C

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7
Q

Methods of decalcification:

A
  1. Acid decalcifying agents
  2. Chelating agents
  3. Ion Exchange Resin
  4. Electrophoresis
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8
Q

The MOST WIDELY USED AGENTS FOR DECALCIFICATION of large amounts of bony tissues because they are stable, easily available and relatively inexpensive

A

Acid decalcifying agents

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9
Q

MOST COMMON and FASTEST DECALCIFYING AGENTS:

A

NITRIC ACID (5-10%)

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10
Q

Nitric acid decalcifying agents:

A
  1. 10% Aqueous Nitric acid
  2. Formol-Nitric acid
  3. Perenyi’s fluid
  4. Phloroglucin-Nitric acid
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11
Q

Decalcifies and softens tissue at the same time.

A

Perenyi’s Fluid

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12
Q

Perenyi’s fluid contains:

A

Nitric acid
Absolute ethyl alcohol
Chromic acid

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13
Q

MOST RAPID (specific) nitric acid and decalcifying agent usually can decalcifies within 12-24 hours

A

Phloroglucin_Nitric acid

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14
Q

REMEMBER:

Nitric acid - MOST FASTEST
Phloroglucin - MOST RAPID

Nitric acid - MOST COMMON decalcifying agent
Formic acid - BEST GENERAL decalcifying agent

A
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15
Q

Nitric acid can impart a yellow color to tissue. However, the addition of ______ to pure Nitric Acid will cause the discoloration to disappear

A

0.1% UREA

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16
Q

Recommended for SURFACE DECALCIFICATION

A

Hydrochloric acid (HCl)

17
Q

Decalcifying agent that contains hydrochloric acid (36%). It contains SODIUM CHLORIDE
HYDROCHLORIC ACID
DISTILLED WATER

A

VON EBNER’S FLUID

18
Q

USED BOTH AS FIXATIVE AND DECALCIFYING AGENT:

A
  1. Formic acid
  2. Chromic acid
  3. Trichloroacetic acid
  4. Sulfurous acid
19
Q

The BEST GENERAL DECALCIFYING AGENT

A

FORMIC ACID

20
Q

Carcinogenic decalcifying agent, corrosive to skin and mucus membranes

A

CHROMIC ACID

21
Q

A “WEAK” decalcifying agent

A

Trichloroacetic acid

22
Q

A “VERY WEAK” decalcifying agent

A

SULFUROUS ACID

23
Q

Substances that combines with calcium ions and other salts to form weakly dissociated complexes and facilitate removal of calcium salts ideal for ELECTRON MICROSCOPY, ENZYME AND IMMUNOHISTOCHEMICAL STAINING

A

CHELATING AGENTS

24
Q

MMOST COMMON CHELATING AGENT in the market; recommended for detailed microscopic studies; SLOW DECALCIFYING AGENT because small specimens may take 1 to 3 weeks while dense cortical bone may take 6 to 8 weeks or longer

A

EDTA (Versene) (ethylenediamine tetraacetic acid)

25
Q

Chelating agents:

A
  1. EDTA (VERSENE)
  2. CAL-EX
26
Q

Ion exchange resins are SUITABLE/NOT SUITABLE for fluids containing mineral acids

A

NOT SUITABLE

27
Q

Decalcifying agent (Formic acid) is usually ________ the volume of the tissue

A

20 to 30 times

28
Q

Process whereby calcium ions which are positively charged are attracted to a negative electrode and removed decalcifying solution satisfactory for small bone fragments

A

ELECTROPHORESIS

29
Q

SOLUTIONS USED FOR ELECTROLYTIC DECALCIFICATION

A
  1. Formic acid (88%)
  2. Concentrated HCl
  3. Distilled water
  4. Sodium chloride
30
Q

TISSUE SOFTENERS:

A
  1. Perenyi’s fluid
  2. Lendrum’s method - use a 4% Phenol solution
  3. Molliflex
  4. 2% HCl
  5. 1% HCl in 70% alcohol

mnemonic:
“Hyd Mo PePhe mong Soft”

31
Q

TESTS TO MEAURE COMPLETENESS OF DECALCIFICATION

A
  1. Physical or Mechanical test
  2. X-ray or Radiological test
  3. Chemical test (Calcium oxalate test)
32
Q

This is done by TOUCHING, PROBING or BENDING resistance to finger nail or by needling 9pricking using fine needle or probe); Most unreliable method

A

Physical or Mechanical test for measuring completeness of decalcification

33
Q

MOST IDEAL, most sensitive, and MOST RELIABLE METHOD of determining extent of decalcification

A

X-ray or Radiological test

34
Q

This is the MOST SENSITIVE test for detetcing calcium in bone or tissue calcification

A

RADIOGRAPHY

35
Q

Simple, reliable and convenient method recommended for ROUTINE PURPOSES to detect presence of calcium in decalcifying solution

A

Chemical test (Calcium oxalate test)

36
Q

A solution used to SCREEN the presence of calcium salts

A

Ammonium hydroxide

37
Q

A solution used to CONFIRM the presence of calcium salts

A

Ammonium oxalate